Symphyotrichum tenuifolium
Symphyotrichum undulatum
perennial saltmarsh American-aster, perennial saltmarsh aster
wavy-leaf American-aster, wavyleaf aster, waxyleaf aster
1–5+, ascending to erect (often with purple or purplish brown areas, flexuous, wiry), little-branched, usually glabrous, sometimes hairy in lines distally.
1–3+, erect (straight, brittle), hirtellous to glabrescent proximally to densely hirtellous distally.
thick (fleshy), margins entire, faces glabrous;
basal withering by flowering (new winter rosettes appearing at flowering), petiolate (petioles sheathing), blades ovate or oblanceolate, 15–20 × 5–15 mm, bases cuneate, apices rounded;
proximal cauline withering by flowering, usually sessile, blades lanceolate, linear-lanceolate or -oblanceolate, to linear, 7–80(–150) × 1–6 (–12) mm, bases attenuate, margins entire, apices acuminate to acute;
distal sessile, blades narrowly lanceolate to subulate, 10–110 × 0.5–5 mm, apices acuminate.
thin, margins scabrous, abaxial faces hirtellous, densely so on midveins, adaxial usually scabrous, sometimes strigose or hirsute, rarely glabrate;
basal withering by flowering (sometimes new winter rosette developing), petiolate (petioles purplish, narrowly winged, bases dilated and sheathing, hirsute), blades oblong-ovate or ovate to widely ovate, (10–)35–60(–140) × (10–)15–70 mm, bases usually cordate or subcordate to rounded, sometimes attenuate, margins shallowly crenate-serrate to subentire, apices obtuse or rounded, mucronulate;
proximalmost cauline withering by flowering, proximal persistent, winged-petiolate, distally more widely winged or ± sessile, wings widening abruptly at strongly auriculate-clasping petiolar bases, blades ovate to lanceolate, 30–120(–140) × (10–)20–50 mm, reduced distally, bases cordate- or auriculate-clasping (sessile), margins crenate-serrate or entire, apices acute or acuminate, mucronate;
distal sessile, blades lance-ovate to oblong or lanceolate to linear-lanceolate, sometimes pandurate (branch leaves ovate to lanceolate, sharply smaller), 4–100 × 0.5–26 mm, reduced distally, bases ± clasping, sheathing, margins serrulate or entire, apices acute or acuminate to long-acuminate.
0.6–4 (–6) cm, bracts 2–8, awl-shaped, grading into phyllaries.
well developed, 0.3–3(–5) cm, branches to 10 cm, spreading, bracteate, densely hirtellous to strigillose, bracts 3–10+, firm, appressed, subulate (2–3 mm), grading into phyllaries.
narrowly turbinate, 4.1–9.5(–11) mm.
campanulate to cylindro-campanulate, 3.8–5.5 mm.
10–25;
corollas white or pink, laminae (4.5–)5–8.5(–9.5) × 1.2–2 mm.
12–16(–25);
corollas usually blue to purple, sometimes lilac, laminae 6–12 × 1.4–2.5 mm.
25–45(–54);
corollas yellow becoming purplish, 3.4–6(–6.8) mm, tubes shorter than to equaling the narrowly funnelform throats (sparsely hairy at base), lobes ± erect, narrowly triangular, 0.5–0.8 mm.
15–22(–25);
corollas cream or light yellow becoming purple, 4–5.8 mm, tubes slightly shorter than funnelform throats, lobes lanceolate, 0.5–0.9 mm.
in 4–5 series, lanceolate to subulate, bases indurate, rounded, margins hyaline, often tinged with purple, entire, green zones spatulate to oblanceolate-rhombic, apices acute, adaxial faces glabrous or minutely hairy distally.
in 4–5(–6) series, appressed or outer spreading, oblong-lanceolate (outer) to linear-oblanceolate (inner) or linear (innermost), strongly unequal, bases indurate 1/2–2/3, margins scarious, erose, hyaline, ciliolate, green zones diamond-shaped to lanceolate, apices acute to acuminate or obtuse, often ± involute, often mucronulate, sometimes tips purplish, abaxial faces hirsutulous, adaxial sparsely so distally.
(1–)3–20(–40), in open, diffuse, paniculiform arrays, branches patent.
in open, narrow to wide paniculiform arrays, branches widely spreading, divaricate to ascending, sometimes secund, ± densely leafy.
light brown, narrowly obovoid to fusiform, sometimes ± compressed, 1.5–4(–4.5) mm, 5–6-nerved, faces sparsely strigillose;
pappi tawny to white, 3–6.1 mm.
dull purple to light brown or tan, oblong-obovoid, compressed, 1.7–2.2 mm, 3–4-nerved, faces strigillose;
pappi cream or rose-tinged, 3.5–5 mm.
= 16, 32.
Symphyotrichum tenuifolium
Symphyotrichum undulatum
Varieties 2 (2 in the flora).
Along the Gulf of Mexico Coast in central and northern peninsular Florida, vars. tenuifolium and aphyllum intergrade in nearly all characters (S. D. Sundberg 2004). G. L. Nesom (2005d) treated the varieties as species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Symphyotrichum undulatum is of conservation concern in Illinois and Nova Scotia. Hybridization with S. drummondii and S. oolentangiense has been by reported by A. G. Jones (1989), but some specimens so annotated represent phenotypic variation of S. undulatum. Symphyotrichum undulatum is sometimes confused with members of the S. patens complex due to its auriculate-clasping, more or less pandurifom cauline leaves.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Stems 1, rhizomes long; mid leaves (1.5–)3–6 mm wide; involucres 6–9.5(–11) mm; ray florets (12–)17–25; disc florets 25–45(–54), corollas (4–)4.7–6(–6.5) mm; cypselae 2.8–4(–4.5) mm; pappi 5–6.1 mm | var. tenuifolium |
1. Stems 1–5+ (clustered), rhizomes short; mid leaves (1–)1.5–2.7 mm wide; involucres 4.1–5.3 mm; ray florets 10–16; disc florets (10–)13–23, corollas 3.4–4.6 mm; cypselae 1.5–2(–2.5) mm; pappi 3–4.4 mm | var. aphyllum |
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